In a long-standing practice in the tobacco industry, tobacco samples are examined for water content by heating in an oven. In such practice, the sample is subjected to oven heating for a standardized length of time at a predetermined temperature. The water content, expressed as oven volatiles (O.V.), is calculated from the weight loss in this process.
Two evident disadvantages attend such oven volatilization practice. Firstly, an extended time period is required. Secondly, for many materials containing oven volatiles, the rate of volatilization of water exceeds the rate of volatilization of other volatiles during early heating stages, whereas the converse is true of such rates as heating progresses into final heating stages. Thus, in such extended heating practice, the observed weight loss can be substantially different from actual weight loss attributable to water volatilization. Water content calculation based on observed weight loss over extended heating accordingly may have inherent inaccuracy.